New Alternative Donor−Acceptor Arranged Poly(Aryleneethynylene)s and Their Related Compounds Composed of Five-Membered Electron-Accepting 1,3,4-Thiadiazole, 1,2,4-Triazole, or 3,4-Dinitrothiophene Units:  Synthesis, Packing Structure, and Optical Properties

Abstract

A series of new poly(aryleneethynylene)-type π-conjugated copolymers, which consist of an electron-accepting 1,3,4-thiadiazole, 4-alkyl-1,2,4-triazole, or 3,4-dinitrothiophene unit and an electrondonating 1,4-didodecyloxybenzene or N-dodecylpyrrole unit, were prepared in 81-93% yields by palladiumcatalyzed polycondensation. Their related model compounds (PhC≡C-Ar-C≡CPh; Ar ) the electronaccepting unit) were also synthesized. GPC traces of the polymers gave number average molecular weights (M n's) of 6900-29 700. The polymers formed a molecular assembly and a birefringent phase as revealed by powder X-ray diffraction (XRD) analysis and polarized light optical microscopy (POM). They formed an aligned structure on a platinum plate. The UV-vis peaks of the polymers appeared in the range of 385-522 nm in solutions, and the peak was shifted by 10-44 nm to a longer wavelength in films, according to intermolecular electronic interaction. The density functional theory (DFT) calculations supported the presence of strong intermolecular interaction between the polymer molecules. The polymers composed of a 1,3,4-thiadiazole or a 1,2,4-triazole unit exhibited photoluminescence with quantum yields of about 50% in chloroform. The polymers were electrochemically active and showed the reduction peak in a range of -1.1 through -2.2 V vs Ag + /Ag.

Self-assembly and charge transport properties of a benzobisthiazole end-capped with dihexyl thienothiophene units

“…17 This strategy avoids trap states 18 that are often seen with pentacene and related materials, leading to instability in air. There has been interest lately in conjugated materials incorporating electron-deficient heterocycles, such as [1,3,4]thiadiazoles [19][20][21][22][23] and dibromobenzo [1,2-…”

Optoelectronic and Semiconducting Properties of Conjugated Polymers Composed of Thiazolo[5,4-d]thiazole and Arene Imides Linked by Ethynylene Bridges

“…5,6 During the last years, we have investigated the molecular structure and electronic properties of series of PAEs containing Th as electron-accepting group linked to phenylene and -C≡C-bridges by means of Density Functional Theory (DFT) calculations. [19][20][21][22][23] Their interesting electronic properties make them suitable candidates for their use as organic semiconductors.…”

A theoretical and experimental study of non-linear absorption properties of substituted 2,5-di-(phenylethynyl)thiophenes and structurally related compounds

“…Because such a shift will result in more coloured samples, the alternative structure S1-NO2b, with the nitro groups in positions 3 and 4 in the ring, was also examined theoretically. In this configuration, with adjacent NO 2 groups, the N and O atoms cannot be coplanar with the ring atoms due to steric reasons [51]. A twist of the NO 2 groups relative to the ring plane was also found by the calculations.…”